1. Field of the Invention
This invention relates to an elevator control apparatus which is designed to estimate the time required for each elevator car to reach each floor with a high degree of accuracy to perform elevator control which copes with various traffic statuses on the basis of the estimated time.
2. Description of the Related Art
In conventional elevator apparatus with a plurality of elevator cars incorporated therein, group control operation is generally conducted. Examples of such group control operation include the allocation method which is directed to improvement in the operation efficiency of the elevator apparatus and to shortening of the waiting time for a car. To achieve these objects, in the allocation method, an evaluated value for each car is operated immediately after a hall call is registered. The car having the best evaluated value is selected as the car to be allocated and is made to respond to the hall call.
To determine the evaluated value, the estimated waiting time for the hall call is generally used. In the elevator group control apparatus disclosed in, for example, Japanese Patent Publication No. 48464/1983, when a hall call is registered, the sum of the squares of all the estimated waiting times for the hall call when the hall call is virtually allocated to each car is obtained as the evaluated value of each car, and a car having the minimum evaluated value is selected as the car to be allocated.
In that case, the estimated waiting time is obtained by adding the period of time during which the hall call continues (the time which has elapsed by the present time after the hall call is registered) to the estimated travel time (the time required for the car to travel from the present position to the floor where the hall call is made).
The use of the thus-obtained evaluated value enables the waiting time for the hall call to be shortened (particularly enables the number of hall calls requiring waiting for more than one minute to be reduced).
However, inaccuracy of the estimated travel time makes the obtained evaluated value insignificant as the reference value with which a car to be allocated is selected, and thus hinders shortening of the waiting time for the hall call. Hence, accuracy of the estimated travel time greatly affects the performance of the group control apparatus.
The conventional methods of calculating the estimated travel time will now be described concretely.
Assuming that the car moves up and down between the two end floors, the estimated travel time is calculated in the manner described in Item (A).
(A) The time (travel time) required for the car to reach the target floor is calculated from the distance between the car position to the target floor, and then the time (stopping time) required for the car to stop at the floors located between the car position to the target floor is obtained. Thereafter, these two times are added to obtain the estimated travel time (Japanese Patent Publication Nos. 20742/1979 and 34978/1979). PA1 (B) The estimated travel time is corrected in accordance with the car state at the floor where the car is positioned (whether the speed of travel is being reduced, the door opening operation is being performed, the door is being opened, the door closing operation is being performed, the car is travelling). PA1 (C) The number of passengers who get on or get off the car at the floor where the car is to make a stop is detected using a detection or estimation device, and the estimated travel time is corrected in accordance with the obtained values (Japanese Patent Publication No. 40072/1982 and Japanese Patent Laid-Open No. 162472/1983). PA1 (D) The difference in the time required for the passengers to get on or get off the car due to whether the car stops the floor where the car is to make a stop in response to the car call or hall call is considered, and the estimated travel time is corrected with that difference taken into consideration (Japanese Patent Publication No. 40072/1982). PA1 (E) The stopping time at each floor is estimated on the basis of the data obtained for each floor from the statistics of the actual stopping time (including the time required for the door opening operation to be made, the time required for the passengers to get on or get off the car, and the time required for the door closing operation to be made) or the door opening time obtained by simulation and incorporated in the group control apparatus (Japanese Patent Laid-Open Nos. 275382/1989 and 138579/1984). PA1 (F) The number of car calls to be generated when the car stops at the floors located between the present car position to the target floor in response to the hall call made on those floors is estimated on the basis of the statistical data on the number of passengers who get on the car, and the stopping time generated by the car calls to be generated when the estimated number of car calls is distributed to the floors located in advance of the target floor in accordance with the statistical probability distribution of the generated car calls is estimated (Japanese Patent Publication No. 34111/1988). PA1 (G) The probability with which the car stops at each floor and in each direction is calculated from the measured values of the number of times the car changes its direction and of the number of passengers who get on or get off the car in each direction, and the estimated travel time is corrected on the basis of the results of the calculation (Japanese Patent Laid-Open No. 26872/1984). PA1 (H) The stopping time generated by the car call at each floor is estimated from the rate with which the passengers get off the car at each floor which is obtained for each floor in each direction (Japanese Patent Publication No. 64383/1988). PA1 (I) The time required for the car to reach the farthest floor located in the direction in which the car proceeds and the time required for the car to travel from that floor to the floor in the opposite direction where the call is made are obtained so as to operate the estimated travel time (Japanese Patent Publication No. 16293/1979). PA1 (J) Assuming that an empty car whose direction of travel has not yet set directly goes to each floor, the estimated travel time thereof is operated (Japanese Patent Publication No. 8621/1984). PA1 an input data conversion means for converting traffic data, including a position of the car, a direction of a movement and calls to be responded, to data that can be used as input data of a neural net; PA1 an estimated travel time operation means including an input layer for taking in the input data, an output layer for outputting the estimated travel time, and an intermediate layer provided between said input and output layers and in which a weighting factor is set, said estimated travel time operation means constituting said neural net; and PA1 an output data conversion means for converting the estimated travel time output from said output layer into data that can be used for a predetermined control operation.
To improve the accuracy with which the stopping time at the floor where the car is positioned or at the floor where the car is to make a stop is estimated, the following estimating methods have been proposed.
To improve the accuracy with which the travel time is estimated when the possibility that a hall call is made on the floor where the car is not to make a stop and the car thus stops at that floor is considered, the following proposals from (F) to (H) have been made.
The direction of travel of the car is often changed at the floor located between the present car position and the target floor due to the uppermost or lowermost call. In order to prevent generation of errors between the estimated travel time and the actual travel time in that case, the direction of travel of the car may be changed at the floor located between the present car position and the target floor before the car reaches the final floor. The following proposals from (I) to (J) cope with that case.
In that case, the upper reversing floor (the floor at which the car changes its direction in response to the uppermost call) is set to the floor to which the uppermost call is made, and the lower reversing floor (the floor at which the car changes its direction in response to the lowermost call) is set to the floor to which the lowermost call is made. However, when the upper reversing floor is set, if the ascending floor call is made at the floor located between the current car position to the uppermost floor, generation of new car call must be estimated. This makes the accurate setting of the uppermost reversing floor difficult. Similarly, accurate setting of the lower reversing floor is also difficult. After all, estimation of another condition, such as reversing floor, increases generation of errors.
Japanese Patent Laid-Open No. 275381/1989 discloses a group-control apparatus which selects the car to be allocated to the hall call on the basis of the operation conducted using the neural net corresponding to the neurons of the human's brain. However, no consideration is given to the improvement of the accuracy with which the estimated travel time is operated.
As stated above, in the conventional elevator control apparatus, various elements, including the present status of the car, the estimated number of passengers who get on or get off the car on each floor the car stops, the type of the present responding call, estimation of generation of the car call, estimation of allocation to a new hall call, estimation of the floor where the car changes its direction, and the current traffic on each floor, are taken into consideration in order to operate the estimated travel time with a high degree of accuracy. However, estimation of these elements with ever-changing complicated traffic taken into consideration makes the operation expressions for the estimated travel time more complicated. Now that there is a limitation to the human ability, complicated operation expressions make development of new operation expression which ensures improved operation accuracy difficult. Furthermore, detailed estimation increases the time required for the operation. This makes quick allocation of the car and forecasting of the estimated travel time impossible.